Fuel injectors are widely used in internal combustion engines where they are arranged in order to inject fuel into an intake manifold of the internal combustion engine or directly into a combustion chamber of a cylinder of the internal combustion engine. The fuel injectors of a multicylinder internal combustion engine are connected to a fuel source known as a common rail to which each of the fuel injectors is hydraulically and mechanically connected through a fuel injector cup. The injector cup itself is connected to the common rail through a supply pipe, through which fuel under high-pressure is supplied to the fuel injector via the cup.
Such cup assemblies are known from the prior art, see for example, U.S. Pat. No. 8,424,509. The cup is adapted to receive the inlet end of a fuel injector on the downstream side of the cup opposite the fuel pipe. Because of the high pressures involved in the fuel injection, there is a need for a clamping force to secure the fuel injector to the injector cup. In these known arrangements, the inlet end of the fuel injector is located in the injector cup and is hydraulically sealed by means of a sealing ring on the injector which engages with the injector cup.
The fuel injector is secured to the engine and the injector cup is also secured to the engine but inevitably the point at which the injector cup is secured to the engine is spaced from the axis of the injector cup and the injector. The pressure of fuel injection tends to urge the injector cup away from the fuel injector and the consequence is that a bending moment is imposed in the connection which tends to separate the connection between the injector cup and the fuel injector. This not only adversely affects performance but can also cause separation between the connector injector cup and the fuel injector particularly with the risk that the injector can be moved to such an extent that the sealing ring can project out of the injector cup with the risk of substantial damage. The prior attempts to minimise this risk result in a substantial construction for the injector cup and also the provision of a flexible clamp arrangement which generates a bending moment in the opposite direction to the bending moment caused by the fluid pressure.
CN 102345544 A provides a fuel supply system of a Vee engine, which reduces the stress applied on an end part of a connecting pipe connecting between a high pressure fuel pump and a transmission pipe. The fuel inflated by a high pressure fuel pump is distributed on a plurality of ejectors arranged on a first cylinder set and a second cylinder set via a first connecting pipe and a second connecting pipe and a first transmission pipe and a second transmission pipe. Because direction of a connecting part at a high pressure fuel pump side of the first connecting pipe and the second connecting pipe is generally consistent with the direction of thermal expansion of the first cylinder set and the second cylinder set, even though the position of the connecting part at the first transmission pipe and the second transmission pipe sides of the first connecting pipe and the second connecting pipe is moved due to the influence of thermal expansion, large stress generated at the connecting part at the high pressure fuel pump side can be avoided; and endurance of the first connecting pipe and the second connecting pipe can be increased.
EP 1967728 B1 discloses a coupling device for hydraulically coupling a fuel injector to a fuel rail of a combustion engine comprising a fuel injector cup being designed to engage a fuel inlet portion of the fuel injector, and a tube with a first end and a second end, the first end being coupleable to the fuel rail and the second end being coupled to the fuel injector cup.